SELECTIVE PLASMA DEPOSITION

The use of selective deposition offers the possibility of depositing m aterials directly onto designated areas of a substrate. Previously, th in films have been deposited selectively using chemical vapor depositi on (CVD), electroless deposition and bias sputter deposition. Selectiv e deposition by any of these techniques has been demonstrated for only a limited range of materials and sources. A novel deposition techniqu e, i.e. selective plasma deposition, is demonstrated, which offers the potential of selective deposition for a wide range of materials. The basic principle of selective plasma deposition is the removal of a wea kly bound species through the combined use of ion bombardment and reac tive plasma chemistry. The key to the removal of the deposited species is the modification of the surface binding energy E(SB). E(SB) may be increased or decreased, depending on the reactive plasma constituents . To demonstrate this process, TiW was selectively deposited on patter ned Al contacts on Si wafers. Although selective bias sputter depositi on in pure Ar can be used to deposit TiW selectively, the selectivity of the deposition is enhanced by the use of a F-containing gas mixture . In a separate series of experiments, aluminum oxy-nitride (AlxOyNz)u lating films were selectively deposited on the Si substrates rather th an the patterned Al.